Effect of Modulating Spin-Coating Rate of TiO2Precursor for Mesoporous Layer onJ-VHysteresis of Solar Cells with Polar CH3NH3PbI3Perovskite Thin Film

Qi Li,Yaxian Pei,Yuanyuan Li,Shuangxiong Zeng,Xiaoping Zou,Dongdong Guo

doi:10.1155/2017/8107073

Abstract

Compared with the crystalline Si solar cells, theJ-Vcharacteristics of CH3NH3PbI3perovskite solar cells are different under forward and reverse scan, and the CH3NH3PbI3film exhibits some polarization properties. To explore those performances of the mesoporous TiO2layer based perovskite solar cells, we focus on the effect of modulating the spin-coating rate of the TiO2precursor for mesoporous layer onJ-Vhysteresis of solar cells with the polar film byJ-Vcurves, atomic force microscopy topographic images, and piezoresponse force microscopy phase images. Firstly, the AFM images illustrate that the polarization behaviors exist and the deformation scale is large at the corresponding position when the DC bias voltage increases. Secondly, it is suggested that the polar films which applied the positive DC biases voltage show a tendency to 0° phase angle, while the polar films which applied the negative DC biases voltage show a tendency to −180° phase angle. Thirdly, a weak polar hysteresis loop relation for CH3NH3PbI3film was observed. Finally, the hysteresis index for the 1500 rpm mesostructured solar cell shows relatively lowJ-Vhysteresis compared with the 3000 rpm mesostructured and the planar-structured solar cell. Our experimental results bring novel routes for reducing the hysteresis and investigating the polar nature for CH3NH3PbI3material.

Highlights

Aiming at next-generation solar cells, the CH3NH3PbI3 perovskite as a light harvester has been widely used in solar cells owing to its low cost and outstanding desirable properties [1]
We study the effect of spin-coating rate of TiO2 precursor for mesoporous layer on HI of CH3NH3PbI3 perovskite solar cells
To investigate the polarization behaviors and local hysteresis phenomenon of the CH3NH3PbI3 films, the topography and the dielectric response of the CH3NH3PbI3 films were measured by AFM

Summary

Introduction

Aiming at next-generation solar cells, the CH3NH3PbI3 perovskite as a light harvester has been widely used in solar cells owing to its low cost and outstanding desirable properties [1]. The efficiency, stability, and large area of the CH3NH3PbI3 perovskite solar cells are the main focuses, while the polarization behaviors of CH3NH3PbI3 perovskite film and J-V hysteresis of CH3NH3PbI3-based perovskite solar cells receive insufficient attention and evolve slowly. Dualeh et al first reported the J-V hysteresis of CH3NH3PbI3-based perovskite solar cells [2]. Kim and Park investigated effects of perovskite crystal size and mesoporous TiO2 layer on J-V Hysteresis of CH3NH3PbI3 perovskite solar cells [8]. They reported on ferroelectric polarization behavior in CH3NH3PbI3 perovskite in dark and under illumination [9]. The low conductivity of the contact materials (TiO2 or HTMs) is one of reasons for the high J-V hysteresis [11, 12]

Methods

Results

Conclusion